The invention relates to a method for producing plastic molded parts with an integrated conductor path, for example for subsequent processing to an electrically heatable mirror. Preferred application is the production of electrically heatable outside rearview mirrors for automobiles.
EP 0 732 865 B1 discloses a molded part with a heating device, in particular an outside rearview mirror of an automobile. The conventional outside rearview mirror includes a heating device having carbon fibers which are connected for current conduction and reinforced with a binder. The carbon fibers together with the binder form a fleece of carbon fibers, with free spaces disposed between the carbon fibers in the fleece. The fleece is overmolded with an electrically insulating plastic material in an injection molding process, wherein the plastic material also penetrates the free spaces. The carbon fibers in the finished molded body are then completely enclosed by the electrically insulating plastic material, with the exception of the current connecting lines.
WO 2008/006483 A1 discloses another embodiment of an electrically heatable outside rearview mirror for an automobile. The outside rearview mirror is manufactured by applying a conductor path made of a resistance material on the front side of a fleece with a thermal injection molding process according to DIN EN 657, whereby the rear side of the fleece is subsequently back-injected with a plastic material. In this way, the plastic material forms simultaneously the carrier plate for the mirror glass, which is attached on the front side of the fleece with an adhesive or an insulating varnish. Both mineral glass and transparent substrates made of thermoplastic or thermosetting materials can be used as mirror glass, with the reflection layer being applied on the side of the carrier plate.
The aforedescribed state-of-the-art has the disadvantage that the outside rearview mirrors are produced from several individual parts in several process steps, which disadvantageously affects the rejection rate.
Based on this state-of-the-art, it is the object of the invention to provide an improved method for producing a plastic molded part as a base for an outside rearview mirror, which is distinguished by a high degree of automation and which has a comparably low rejection rate. In addition, a flat optical surface without depressions should thus be achieved.